1. Field of the Invention
This invention relates generally to a surgical navigation system. More particularly, this invention relates to a system, a tracking device, and an adapter to assist the surgical navigation system orient a surgical instrument or device relative to a body of a patient.
2. Description of the Background of the Invention
The use of image guided surgical navigation systems for assisting surgeons during surgery is quite common. Such systems are especially widely used during procedures requiring precise location of instruments such as neurosurgery and more recently orthopedic surgery. Typical surgical navigation systems utilize specially developed tools that include built in tracking devices or tool and adapter combinations that allow a tracking device to be affixed to a surgical tool. These tracking devices allow a surgeon to see the position and/or orientation of the surgical tool overlaid on a monitor in conjunction with a preoperative image or an intraoperative image of the patient. Preoperative images are typically prepared by MRI or CT scans, while intraoperative may be prepared by using a fluoroscope, low level x-ray or any similar device. The tracking devices typically use a plurality of optical emitters that can be detected by the navigation system to determine the position and orientation of the surgical instrument.
One of the main challenges with present surgical navigation systems is the time required to properly apply and calibrate the tracking devices to work with conventional surgical instruments. Raab U.S. Pat. No. 5,251,127 teaches a computer aided surgery apparatus for positioning a surgical instrument that employs a computer driven instrumented linkage attached to a surgical instrument. Foley et al. U.S. Pat. No. 6,021,343 discloses a handheld surgical instrument with a tracking device that requires pre-dedicated and specially made surgical tool connections. Kienzle, III et al. U.S. patent application No. 2001/0036245 is directed towards a surgical tool with integrated localizing emitters for superimposing a representation of the tool over an image of a body in surgery.
Dedicated adapters for surgical instruments are expensive and time consuming to develop. Additionally, most of these devices require calibration of the surgical instrument after the tracking device has been attached in order to determine the transformation between the tracking device and an axis of the instrument. Moctezuma de la Barrera et al. U.S. patent application Ser. No. 10/246,599 teaches a surgical instrument fixedly attached to a tracking device, wherein the calibration of the position and orientation of the surgical instrument is accomplished by a separate device. In addition, for orthopedic surgery, it is sometimes necessary to apply force to the surgical tool. This force can damage the precision tracking device, such as damaging the electronics, the LEDs, or disturbing the calibration of the tracking device, if the tracking device is firmly attached to the tool when the force is applied. The present device allows a surgeon to track the orientation of the effector axis or effector plane of a wide range of instruments without the need to either calibrate the tool tracker combination or fixedly attaching a tracking device to a surgical instrument. In addition, the devices of this invention can be used to place items in the body in precise locations. One example of devices that must be properly placed are shunts that are place in the brain to drain fluid.